1. Field of the Invention
The present invention relates to a scroll compressor, and particularly, to an apparatus for preventing backflow of a gas of a scroll compressor capable of preventing a gas, which has been discharged toward a condenser through a discharge pipe after compressed at a compression unit, from backflowing into a compressor, namely, into a hermetic container.
2. Description of the Background Art
In general, a compressor converts electric energy into kinetic energy, and compresses a refrigerant gas by the kinetic energy. The compressor is a core factor which constitutes a freezing cycle system, and there are various kinds of compressors according to a compression mechanism, such as a rotary compressor, a scroll compressor, a reciprocal compressor and the like. Such compressors are utilized in a refrigerator, an air conditioner, a showcase and the like.
The scroll compressor comprises a motor unit generating a rotary force; and a compression unit for sucking, compressing and discharging a gas as an orbiting scroll orbits in meshing engagement with a fixed scroll upon receiving a driving force of the motor unit.
FIG. 1 is a longitudinal sectional view mainly showing a compression unit of a general scroll compressor.
As shown, the compression unit of the scroll compressor includes: a fixed scroll 30 mounted in a hermetic container 10 at a certain distance from a main frame 20 mounted in the hermetic container 10; an orbiting scroll 40 positioned between the fixed scroll 30 and the main frame 20 and orbiting in meshing engagement with the fixed scroll 30; an Oldham ring 50 positioned between the orbiting scroll 40 and the main frame 20, for preventing a self-rotation of the orbiting scroll 40; a separation plate 11 coupled to the fixed scroll 30 and the hermetic container 10, for separating the inside of the hermetic container 10 into a high pressure area (H) and a low pressure area (L); and a valve assembly 60 mounted at an upper surface of the fixed scroll 30, for opening and closing a discharge hole 31 formed at the fixed scroll 30.
And the orbiting scroll 40 is connected to an eccentric portion 71 of a rotary shaft 70 inserted in the main frame 20.
A suction pipe 12 through which a gas is sucked is coupled to one side of the hermetic container 10, where the low pressure area (L) is placed, and a discharge pipe 13 through which a gas is discharged is coupled to one side of the hermetic container 10, where the high pressure area (H) is placed.
Non-explained reference numeral 32 is a wrap of the fixed scroll 30, which is protrudingly formed as an involute shape, 41 is a wrap of the orbiting scroll 40, which is protrudingly formed as an involute shape, and ‘P’ is a compression pocket.
The operation of the compression unit of the scroll compressor having such a structure will now be described.
First, when the rotary shaft 70 rotates upon receiving a rotary force of the motor unit, the orbiting scroll 40 coupled to the eccentric portion 71 of the rotary shaft orbits about the center of the rotary shaft 70. The orbiting scroll 40 orbits without making a self-rotation, thanks to the Oldham ring 50.
The wrap 41 of the orbiting scroll 40 orbits in meshing engagement with the wrap 32 of the fixed scroll 30 according to the orbiting movement of the orbiting scroll 40, so that a plurality of compression pockets (P) formed by the wrap 41 of the orbiting scroll 40 and the wrap 32 of the fixed scroll 30 move toward the central portions of the fixed scroll 30 and the orbiting scroll 40, and simultaneously change their volumes, thereby compressing a gas within the compression pockets. The gas compressed in the compression pockets (P) is discharged through the discharge hole 31 of the fixed scroll 30.
The high temperature high pressure gas discharged through the discharge hole 31 of the fixed scroll passes through the high pressure area (H) and then is discharged outside the hermetic container 10 through the discharge pipe 13. The high temperature high pressure gas having been discharged through the discharge pipe 13 of the scroll compressor flows toward a condenser (not shown) connected to the discharge pipe 13.
Meanwhile, a freezing cycle system including the scroll compressor is commonly mounted at an air conditioner. In such a freezing cycle system, a high temperature high pressure refrigerant gas discharged from the compressor passes through a condenser, a capillary tube and an evaporator.
However, the scroll compressor having such a structure is disadvantageous in that when the freezing cycle system stops operating, a gas which was discharged toward the condenser through the discharge pipe 13 coupled to the hermetic container 10 of the scroll compressor flows backward and is introduced into the hermetic container 10. Thus, in reoperation of the scroll compressor, compression efficiency is degraded.